Strop for safety-razor blades and the like



April 13 19261 l1,580,514.

MQW. MCARDLE s'rnor Fon SAFETY RAZOR BLADES Aun 'ma uns iledua'n. 2a,.1925

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` To all whom t may concern.'

PatentedApr. 13, 1.926.

YUNITED STATES MICHAEL W.;M'cA RnLE, oF CHICAGO, ILLINOIS.

s'rRoI FOR SAFETY-nazonfBLAnEs AND THE LIKE.

Application led January 28, 1925. Serial No. 5,192'.

Be it known that I, MICHAEL XV. Morinnnii, a citizen of the United States, residing in Chicago, in the county of Cookv and the State of Illinois, have invented certain new and useful Improvements in Strops for Safety- Razor Blades and the like, of which thefollowing is a specification, reference being .hadr to the accompanying drawings, formingv a part thereof.

The purpose of this invention is to provide an improved device ofthe nature of a strop for a safety razor having straight edges to be sharpened. It consists in the elements and features of construction showii and described, as indicatedin the Claims. A l I In the drawings: n

Figure l is a. perspective view ofa device embodying this invention, showing the inode Y of use in the hands of the user.

Figure 2 is an end elevation of the device shown in Figure 1.

Figure 3 is a section at the line, 3-3, on

Figure :2, showing one form of the means of y securing and tightening the strap and mounting the handle. l

Figure 4 is a detailsection at the line, 4-4, on Figure l for illustrating the co-operation of the fingers of the user with the blade and Sharpener in sharpening.

Figure 5 is a. detail fragmentary view showing the two ends of the strap withdrawn from their lapped position for showing the means by which they are engaged for tightening on the mount in the forni shown in Fig. 3.

Figure 6 is a section at the line, 6-'(3, lon Figure 3. l Figure 7 is a view similar to Figure 3 showing a modified and preferred form of the means for securing and tightening the strap.

Figure Figure 7.

A defect which may be observed in the more customary devices for sharpening razor blades and the like,Y is that the sharpening device,-strap or inflexible sliarpeiier,-is either concave or'at at the surface along which the blade is moved or which is ni'ovable across the blade for sharpening, tend ing to cause the angle of bevel of the edge of the blade which is to be sharpened to be rendered more obtuse, rather than more 8 is a section at theline, 8,-8, on

` ening strap.

blade and like implements,v

acute,-.by the process of stropping or honing. Inthe present invention this defect is avoided and the Contrary tendency is obtained by making the strop surface over which the blade is manipulated for sharpening Convex, 'and with approximately cylindrical forni of curvature. In the. structure shown in the drawings A is a metal mount. for rthe sharp- It is formed of a strip of quite stiff, and preferably somewhat resilient, Inet` al vflexed as. to its middle part in substan` tiallytheforinof a cylindrical segment, the

ends being bent toward each other and lapped to forni `the base of the cylindrical segment. Desirably the two ends lapped at` aare permanently secured together as by spot-welding or the like, and kat their lap are apertured as seen. at al, yat the cent-ral point of the base of the segment form.v The strap, B, is wrapped about the mount, A,

the middle portion extending over the curved portion of the inount.

For securing the ends together and tightening the strap about the mount in the fornishown in F igureB, the construction comprises metal plates, C, C, secured vas' by rivets, o, upon the lapping end portions of the strap,- the strap andthe metal plates being provided with elongated slots, b3 and c, respectively, the metal plates having rack teethl as seen at c, on one side or' the slot, the plates on the two ends of the strap respectively having the rack teeth at the opposite sides of the slot, as 'mayv rbe understood from Figures 5 and 6. A pinion, D, dimeiisioned and toothed for entering the slots and engaging vthe rack teeth at the opposite sides of the slots in the metal plates respectively, isA mounted on a handle, E, which extends down vfrom the center of the base of the segment, having a iange, F, below the pinion, D, said flange being diametered for lappingthe margins of the slot or' the lower or outer-lapped end of the strap. This handle has the reduced end by which it extends through and engages the pinion extended beyond the pinionat the inner or upper side and threaded for receiving a nut,

G, whose diameter is greater than the diamhandle. lFrom this description it may oe understood that when the handle is entered and the pinion thereon engaged with .the racks, C4, C, the rotation of the handle serves to tighten the strap on them'ount,"

and that the nut G, being then tightened, will serve to retain the strap stretched to the desired degree of tightness.

ln the form shown in Figures 7 and 8, instead of the means desciibed and shown in Figures 3, 5 and 6, for securing and tightening the strap, the means for that purpose comprises a clamp fitting consisting ofga nut or bushing, M, diameteied for being entered through the aperture, al, in the base of the mount, A, having a radially projecting flange, m, at the inneil end, having its outer end reduced and threaded at m1, and its axial aperture threaded as seen at m. 'irliis itting is dimensioned as to its length from the inner face of the flange, m, to the shoulder produced by the reduction at the threaded end, m2, for extending through the lapped ends, a, a, of the base of the mount and nearly through the lapped ends of the stiap which are preferably re-eiiforced by metal plates, (Zt, as seen in Figure 7; so that a nut, N, screwed onto the reduced threaded end, n2, against an interposed washer, O, serves to clamp the lapped ends of the strap securely onto the base. In this construction these lapped ends are not slotted and no provision is necessarily made at this point forincreasing the lap for stretching the strap, the strap being dimensioned as to its length for titting fairly snugly around the mount to bring the apertures 'at its ends registered with each other and with the base in the mount. The means for tightening thestrap in this form consists of a strut which as shown comprises a stem, P, and a cross head, R, the cross head extending the entire width of the .mount A, and bearing up against the 'under side vthereof at the vmiddle point, and having at the middle point ofits length a hollow boss, r, in which the end of the stem, P, is seated, This stem is reduced. iii diameter as to its upper portion and threaded for a short dis tance below said reduced portion for screwing through the lit-ting, M, lto project the cross head, R, up against the under side of the cylindrical seatatliorded by the mount for the strap, and whereby, iii view of the resilient yieldingness of the mount it is expanded and thereby tends to stretch the strap mounted thereon. Desirably this threaded stein, l), is iiiade as a continuation of the handle, E and is furnished with a lock nut, T.

lt will be understood from the illustration iii the drawings, and particularly in Figure l, tiiat in the use of this blade strop, the blade, W, being held between thuni-b and linger of the operator, will be positioned as l to its angle to the sharpening` surface of the strap, by the thumb or linger-nail of the operator resting and being kept in contact with the strap as the blade is drawn over the curved surface; and that this prevents the blade being inclined at any time to a tangent of the curve at an angle tending to blunt the blade by reason of the bevel of the cutting edge being less than it should be for maximum efficiency.

I claiinz l, A device for the purpose indicated consisting of Ya mount having an arcuate surface, the same being made of a metal strip formed as to its middle portion in the arc of a segment of a cylinder and having the end portions extending in the plane Of the chord of such segment, and unitedto form the base of the mount, said base being apertured near the middle point, a strap o-f material suitable for blade sharpening purposes stretched on said arcuate surface of the mount; means for securing the strap being a clamping device adapted to pass through said aperture radially flanged at one end and threaded at the other end, and aclamping nut applied to the threaded end, the strap being apertured near its ends and lapped in engagement with said threaded fitting and. clamped thereon between the nut and the outer side of the base of the ino-unt.

2. A device for the purpose indicated consisting of a mount hav-ing an arcuate surface, the same being made of a strip of resilient metal formed as to its middle portion in the are of the segn'ient of the cylinder and having the end portions extending in the plane of the chord of such segment and united to form a base of the mount, Said base being apertured near its middle point; a strap of material suitable for blade sharpening purposes stretched on said `arcuate surface of the mount; means for clamping the strap on the mount by the ends of the strap wrapped and lapping on the base, consisting of a fitting having one end radially flanged, Iind the other end exterior'ly threaded, adapted for insertion through the aperture of the base, and the apertures of the strap, and provided with a nut for screwing onto the threaded ends for clamping the lapped strap ends against the base, said fitting being axially apertured and interiorly lthreaded, and means for tightening the strap consisting of a cross bar seated against the under side of the cylindrical portion of the mount and a stein engaged rotatably with said cross bai' screwed through the clamp fitting and provided with means for rotating it to thrust it against the cross bar'.

8. A device for the purpose indicated consisting of a hollow member having aa arcuate surface having an aperture substantially centrally positioned in the side opposite said arcuate surface, the same constituting a nioun't; a strap for sharpening purposes stretched on and' adapted to en- Wrap the said varcuate surface of mount and lap its ends over said aperture, and

having apertures for substantial registration with the aperture of the base; means for clamping therstrap ends Onto the base at said registering apertures; a strut device extending between said clamping means and the under Side of the curved portion of the mount comprising a cross bar at its bearing under said curved portion, and means for extending the strut between said clamping means and said cross head. 1 In testimony whereof, I have hereunto set my hand at Chicago, Illinois, this 23rd day of January, 1925.

MICHAEL W'. MCARDLE. 

